Could someone please explain the (3) sections that sentence is referring to? Section 220.61(B) seems to be the closest answer I can find.

36 unit apartment building, each dwelling unit supplied by single phase 120/240, 100 amp feeder panel. My question is can grounded conductor to EACH unit be reduced? According to section 220.61(B)(2) & 220.61(C)(1) I would think not.

Not quite sure what you mean by "explain the (3) sections that sentence is referring to?" But I would think the code would allow the reduction of the feeder grounded conductor size amounting to 30% of the range, oven, cooktop and dryer load. It's written kinda goofy but the handbook explains it a little bit. The feeder grounded conductor can be reduced the way I read it. Based on the type of feeder being a Delta.

This text from '08 NEC 220.61 (b)(1) the key word is 'household'(1) A feeder or service supplying household electric ranges, wall-mounted ovens, counter-mounted cooking units, and electric dryers, where the maximum unbalanced load has been determined in accordance with Table 220.55 for ranges and Table 220.54 for dryers

Up2Codeó Your neutral only has to be large enough to carry the maximum calculated unbalance load between the neutral and any one ungrounded conductor. So if your storage units had a total load of 50a. and 30 of those amps were 240v. (figure 120/240v feeder) Then your neutral would only have to be rated 20a. But you have to be careful because your neutral can not be smaller than your Grounding Electrode Conductor if this is Service.